A photosensitive resin composition is widely used for a cured film of various displays such as a liquid crystal display and an organic EL display. Particularly, in a liquid crystal cell of a liquid crystal display, a spacer formed using a photosensitive resin composition may be employed to maintain a gap between upper and lower transparent substrates constant, and the spacer is generally formed by a method including coating a photosensitive resin composition on a substrate, followed by exposure to ultraviolet ray, etc. via a mask, and developing.
In the case where the spacer is applied to a small display having small pixels such as a cellular phone and a tablet PC, the formation of a spacer pattern with high resolution is crucial. Further, elasticity recovery rate that may sufficiently endure external impact onto a touch screen is also crucial.
Elasticity recovery rate is influenced by the number of crosslinking bonds in a composition that are formed through light exposure and thermal curing during performing processes. If the amount of photopolymerizable compound increases in a photosensitive resin composition, the number of crosslinking bonds may be largely increased through light exposure, thereby improving the elasticity recovery rate. However, the mere increase of the amount of the photopolymerizable compound may decrease the number of functional groups that assist the development of a polymer, or increase sensitivity to exposure intensity, thereby increasing the size of a dot pattern and negatively affecting the formation of a pattern with high resolution.
Accordingly, a photosensitive resin composition that may resolve the above-described defects in a development process, improve elasticity recovery rate, and produce a pattern with high resolution is required.
In this regard, Korean Laid-open Patent Publization No. 10-2001-0059259 discloses a photosensitive resin composition comprising a polymer, a polyfunctional acrylate monomer, and a photopolymerization initiator; and a color filter for a liquid crystal display. However, it does not disclose a photosensitive resin composition comprising a photopolymerizable compound containing hepta- or more functional groups.
In addition, Korean Laid-open Patent Publization No. 10-2010-0028486 discloses a photosensitive resin composition comprising (A) a resin having an acid functional group in a side chain, (B1) a hexafunctional polymerizable compound, and (B2) a heptafunctional polymerizable compound, and enduring vibration with high frequency. However, high resolution and good elasticity recovery rate are not disclosed therein.
Therefore, a photosensitive resin composition that may provide high resolution and good elasticity recovery rate, which are required in a cured film, particularly in a spacer of various displays such as a liquid crystal display and an organic EL device, is required.